Have you ever tried a pair of speakers and said this Is the last thing I will ever need.

Interestingly enough the first time I "tried" the speakers I now own I did not care for them.  They were slow, bloated and lacked dynamics.  Most likely the amplifier used was not a good match.
Fast forward a couple years and the Harbeth C7ES3 are not going anywhere.  

I know better. They’ll plant me with new speakers position properly in my casket.

Yes.  My B&W 703 that I bought 14 years ago
 
Sure there are better and more expensive speakers but they play full range , cover all sound qualities & genres and look nice. I intend  it to be my last speaker.

Yes- Thiel CS 2.4/2.4 SE loudspeakers.

Well there sure have been speakers that I would probably like more than what I have but to be honest I am very satisfied with my Ref 3a Decapo BEs with REL sub. After almost 4 years and plenty of tweeking and fine tuning they are sounding quite "right" in my space and right to me has always been the goal. When it is "right" boredom doesn't reveal it's ugly head so much. Of course the room is always the biggest determining factor with speaker choices IME. Much attention has been given to this and the efforts have realized significant improvements.

I have a vintage amp and a 6sn7 tube preamp that sing together all ready for a pair of Quad speakers, 57's or 63's, I wouldn't care. The only problem is I don't have another room to set up for that. The Quads and Soundlabs still provide the most natural, transparent and timbrally accurate sound I have heard. They can be profound in communicating a performance. Maybe in the main room at some point in the future. Other than those speakers I find the Decapos fabulous in my room and with my components, they are also superb communicators.